This invention relates to a rack-pinion steering gear for use in the steering system of an automobile and more particularly, to an improved variable ratio rack-pinion steering gear having an overall steering ratio (the rotation angle of the steering wheel and wheels).
A variety of variable ratio rack-pinion steering gears of the above type and have been proposed hithertofore and some of the prior art variable rack-pinion steering gears are disclosed in British Pat. Nos. 609,356 and 1,356,172, Laid-Open German Patent Application No. 2,223, 527 and U.S. Pat. No. 3,267,763, for example. However, various difficulties are encountered in the manufacture of the variable ratio rack-pinion steering gears disclosed in these patents and patent application. The variable ratio rack-pinion steering gear of British Pat. No. 1,356,172 had the disadvantages that the manufacture of the rack bearings was not easy, the performance of the rack end ball joint was not satisfactory and the strength of the rack teeth is not sufficient. The variable ratio rack-pinion steering gears of British Pat. No. 609,356 and Laid-Open German Patent Application No. 2,223,527 had the disadvantage that the provision of the sleeve on the rack increased the volume of the gear and production cost. The variable ratio rack-pinion steering gear of U.S. Pat. No. 3,267,763 had the disadvantage that the production of the rack teeth was not easy and the speed change ratio was inadequate.